I have heard djembes that "clash" with one another sonically, and that can be as painful as a sour note on other kinds of instruments!
I have never heard djembes clash unless one was out of tune in the first place. You?
I have... though only occasionally. Has a lot to do with the drum's overtones, the sound of X shell with Y skin. (Am talking about the overtones that are inherent in the drum's sound, not excessive ringing, etc.) The "clash" would probably not exist if the drum(s) could be magically reskinned on the spot.
But I do play some instruments that are made entirely of wood (cajon, rhythm bones made of various woods), and i've got instruments that clash with one another, if only ever so slightly.
Back to what James mentioned re. the tuning of a krin - i would assume that it has a great deal to do with each individual piece of wood, in terms of how it is carved, how large the sound chamber is, how thick the "bars" are, etc. It's certainly not as adjustable as bala or marimba keys are, where shaving a bit off a key can alter the pitch in a way that makes it possible to get many, many different notes, scales, etc. (You could do it with krin, but it would take quite a few instruments - and players - to make it work.)